There are mainly three technologies that have been used for micro-electro-mechanical-systems (MEMS) integration and packaging: Chip scale packaging, MEMS on or above CMOS ICs (e.g., application specific integrated circuit (ASIC)) with capping for the packaging, and MEMS and CMOS ASIC interconnect based on through-substrate-vias (TSV) or flip chip bonding. All of these technologies, which require MEMS integration with the electronics (CMOS ICs), have been challenging mainly due to high manufacturing cost, low yield, and lack of integrated packaging solutions.
MEMS-on-glass has been proven to be one of viable solutions for high performance device and low manufacturing cost. A desirable quality of MEMS-on-glass is that devices can be formed on large area relative to when the devices are formed on a silicon substrate. Unfortunately, MEMS-on-glass requires the packaging solution to integrate MEMS devices with the CMOS ASIC devices.
FIGS. 6A, 6B and 6C illustrate examples of conventional packaging of MEMS-on-glass devices with electronics such as ASIC devices. The conventional package 600A illustrated in FIG. 6A comprises a MEMS device 610 formed on a glass substrate 605 and an ASIC device 620. Connections from the MEMS device 610 to an external substrate 645 (e.g., a printed circuit board (PCB)) are provided by through-glass-vias (TGV) 655 and conductive bumps 650. Connections from the ASIC device 620 to the external substrate 645 are provided through the conductive bumps 650 and the wiring on the substrates.
In the conventional package 600B illustrated in FIG. 6B, the MEMS device 610 on the glass substrate 605 are both above the ASIC device 620. Connections from the MEMS device 610 to the ASIC device 602 are provided through the TGVs 655 and the conductive bumps 650. Connections from the ASIC device 620 to the external substrate 645 are provided by wirebonds 665. The conventional package 600C illustrated in FIG. 6C is similar to the conventional package 600B except that the connections from the ASIC device 620 to the external substrate 645 are provided by through-silicon-vias (TSV) 675.
One disadvantage of the conventional packages 600A, 600B, 600C is the high profile. This is mainly due to the thickness of the glass substrate 605, which results in bulky packages. Another disadvantage is that the conventional packages are individually fabricated. An individual MEMS-on-glass device and an individual ASIC device are combined (e.g., the MEMS device 610 is coupled to the ASIC device 620), and the combination is externally coupled to the working substrate 645. Fabricating individual packages can be costly.